Buoyance regulating apparatus for underwater swimming

ABSTRACT

A piston, defining a part of or otherwise operatively associated with an elongated, hollow air chamber, is movable relative thereto for varying the volume of the latter, and is urged resiliently in the direction to reduce the volume of the air pressure chamber. The side of the piston opposite the air chamber is exposed to water in which a swimmer is to submerge, and a passageway communicates the interior of the air pressure chamber with a source of air under pressure, preferably the exhaust breath of the swimmer.

United States Patent UNITED STATES PATENTS 1/1970 Brecht ..61/69 R Dimick 51 Oct. 3, 11972 1 BUOYANCE REGULATING 3,161,028 12/1964 Odum et a1. ..61/69 R APPARATUS FOR UNDERWATER 3,379,023 4/1968 Crose ..61/70 SWIMMING 3,436,777 4/1969 Greenwood ..61/70 X [72] Inventor: Royal H. Dimick, Rm 4, Box 3,541,985 11/1970 Murphy ..61/69 R X Albany 97321 Primary Examiner-J. Karl Bell [22] Filed: Feb. 6, 1970 Attorney-Oliver D. Olson [21] App]. No.: 9,281 [57] ABSTRACT e Apphcahon Data A piston, defining a part of or otherwise operatively [63] Continuation-impart of Ser. No. 755,211, Aug. associated with an elongated, hollow air chamber, is 26, 1968, abandoned. movable relative thereto for varying the volume of the latter, and is urged resiliently in the direction to [52] US. Cl ..61/69, 114/16 reduce the volume of the air pressure chamber. The [51] Int. Cl. ..B63c l1/22, B63g 8/24, 605d 9/00 side of the piston opposite the air chamber is exposed [58] Field of Search ....61/69, 70; 9/8, 313, 314, 316, to water in which a swimmer is to submerge, and a 9/327, 340-342; 137/102; 114/16, 16.3; passageway communicates the interior of the air pres- 128/ 145.7, 142, 142.3;60/22 sure chamber with a source of air under pressure, v preferably the exhaust breath of the swimmer. [56] References Cited 26 Claims, 10 Drawing Figures PATENTEDIIBT3 m2 3.695.048 SHEET 1 [IF 2 I L: Royal HDim-ick BY INVENTOR qlf reni PMENTEnnm m 7 3,695,048

SHEET 2 0F 2 Y Q1 HDimic k INVENTOR BUOYANCE REGULATING APPARATUS FOR UNDERWATER SWIMMING CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my earlier application, Ser. No. 755,211 filed Aug. 26, 1968 now abandoned.

BACKGROUND OF THE INVENTION I This invention relates to underwater swimming apparatus, and more particularly to apparatus for regulating the buoyancy of an underwater swimmer throughout a substantial range of submergence.

Regulation of buoyancy of an underwater swimmer has been achieved heretofore primarily by the use of weight packs or belts to assist the swimmer in submerging to a desired level, whereupon the swimmer jettisons sufficient of the weights to maintain the desired level. Since the jettisoned weights are not recoverable, they represent a substantial expense. Moreover, having jettisoned sufficient weight to maintain a predetermined level of submergence the swimmer cannot, without difficulty, thereafter submerge to greater depths.

. Regulation of buoyancy of an underwater swimmer also has been achieved heretofore by the use of a balance tank open at its bottom end to receive water and connected at its upper end to a source of air under pressure by which to displace water in the tank. This arrangement involves manual adjustment of a valve controlling the source of air under pressure to the tank, and requires substantially continuous attention of the swimmer. Such preoccupation with control represents a disconcerting detraction of the swimmer from his pleasure or duty. Moreover, if the swimmer upends at any level of submergence, directing the open bottom of the balance tank upwardly, water displacement in the tank is increased with consequent loss of buoyance balance at that level. Accordingly, the movements of the swimmer are restricted to the extent that he must maintain an upwardly inclined attitude.

SUMMARY OF THE INVENTIONv a the swimmer.

It is by virtue of the foregoing basic concept that the principle objective of the present invention is achieved,

namely to overcome the disadvantages of prior apparatus as discussed hereinbefore.

Another important object of the present invention is the provision of buoyancy regulating apparatus of the class described which functions advantageously to utilize the exhaust breath of a swimmer as the ,source of air pressure by which to effect buoyancy balancing throughout a substantial range of submergence.

Still another important object of this invention is the provision of buoyancy regulating apparatus of the class described which is of simplified construction for economical manufacture, is light in weight for easy transport, is operable with precision, and has long service life with minimum maintenance and repair.

The foregoing and other objects and advantages of the present invention will appear from the following detailed description, taken in connection with the accompanying drawings of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary vertical elevation illustrating schematically a pack assembly including an underwater air supply and a pair of buoyancy regulating units embodying the features of the present invention.

FIG. 2 is a fragmentary plan view of the assembly illustrated in FIG. 1.

FIG. 3 is a foreshortened, fragmentary vertical elevation, partly in section, illustrating one form of buoyancy regulating apparatus embodying the features of this invention.

FIG. 4 is a fragmentary, foreshortened vertical section illustrating a modified form of buoyancy regulating apparatus embodying the features of this invention.

FIG. 5 is a fragmentary, vertical section illustrating still another modified form of buoyancy regulating apparatus embodying features of this invention;

FIG. 6 is a fragmentary, foreshortened vertical elevation, partly in section, illustrating a still further modified form of buoyancy regulating apparatus embodying the features of this invention.

FIG. 7 is a fragmentary, foreshortened vertical elevation, partly in section, illustrating a further modified form of buoyancy regulating apparatus embodying features of this invention.

FIG. 8 is a sectional view taken along the line 8-8 in FIG. 7.

FIG. 9 is a sectional view taken along the line 99 in FIG. 7.

FIG. 10 is a sectional view taken along the line l0 10 in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring primarily to FIGS. 1, 2 and 3 of the drawing, there is illustrated a conventional form of underwater air supply and breathing apparatus used by underwater swimmers. A tank 10 of compressed air is connected through a shut-off valve 12 and flexible hose 14 to the inlet of a pressure regulator valve 16. The air delivery outlet of the valve communicates with a mouthpiece 18 through which the swimmer takes in the supply air and expels the exhaust air. The exhaust air passes through an exhaust outlet 20 of the valve. Associated with the exhaust outlet, and usually integrated with the regulator valve, is a check valve 22. This check valve functions to allow the exhaust air to pass outwardly through it into the water, but prevents water from passing inwardly through it into the mouthpiece.

A harness is provided for strapping the compressed air tank 10 to the back of the swimmer. For purposes of the present invention such a harness includes means for supporting one or more buoyancy reulating units 24 in addition to the air supply tank. In FIGS. 1 and 2 the harness is shown to accommodate the support of two such buoyancy regulating units, one on each side of the air supply tank. The harness includes a pair of opposed clamp members 26 and 28 contoured to lap substantially semi-circular segments of the air tank and buoyancy regulating units. Bolts 30 or other suitable clamping devices extend through aligned openings in the sections of the clamp members adjacent the semicircular portions, to draw the clamp means together and thus grip the tank and units between them. As best shown in FIG. 2, the clamp members support the three units in a generally curved arrangement conforming to the curvature of the swimmers back. Shoulder straps 32 and chest straps 34 extend from the opposite ends of the clamp members for securing the assembly to the swimmer.

Referring now to F IG. 3 of the drawing, the buoyancy regulating unit illustrated therein includes an outer, elongated, hollow cylinder 36 of substantially rigid structural material, such as metal or plastic, providing an air pressure chamber 38 therein. A flexible tube 40 communicates this chamber with the exhaust air outlet of the regulator valve 16.

The tube 40 may be connected to the exhaust air outlet at the inlet side of the check valve 22. However, in the preferred embodiment illustrated the tube is conne'cted intermediate the ends of a conduit 42, one end of which is connected to the outlet of the check valve 22 and the opposite end of which is connected to the inlet of a second check valve 44. The outlet of the second check valve communicates with the water in which the swimmer is to submerge. Utilization of the two check valves provides the additional safety factor of minimizing the possibility of water being taken in by the swimmer in the event water should accidentally enter flexible tube 40.

A branch tube 40 connected to the tube 40 serves to deliver exhaust air to the pressure chamber of the second unit 24 illustrated in FIGS. 1 and 2.

Means is provided for varying the volume of the air pressure chamber 38 within the cylinder 36. In the embodiment illustrated in FIG. 3 this means comprises an elongated, hollow, longitudinally collapsible bellows 46 of flexible plastic or other suitable non-porous material. The bellows is sealed at its bottom end to the bottom wall 36' of the air cylinder and is closed at its upper end by the piston 48. One or more openings 50 in the bottom wall of the cylinder communicate the interior of the bellows with water in which a swimmer is to submerge. The bellows and piston thus form a part of the air pressure chamber 38 and also form a water chamber 52 which is sealed from the air pressure chamber 38.

Means also is provided for urging the bellows and piston defining the water chamber in the direction to reduce the volume of the air pressure chamber 38. in the embodiment illustrated in FIG. 3 this means comprises an elongated, hollow, longitudinally collapsible bellows 54 positioned concentrically within the water chamber bellows. The bellows 54 is sealed at its bottom end to the bottom wall 36 of the aircylinder and at its top end tothe piston. The bellows thus defines a closed, compressible air space 56 sealed from the air pressure chamber 38 and water chamber 52. Accordingly, as the piston moves downward to increase the volume of the air pressure chamber 38, the air in the bellows 54 increases progressively in pressure and thus provides a resilient force of progressively increasing magnitude opposing downward movement of the piston. The degree of movement of the piston is determined automatically by the balancing of air pressure in the bellows 54 with the water pressure in the water chamber 52 and the exhaust air pressure in the air pressure chamber 38.

In the preferred embodiment illustrated manual means also is provided for adjusting the air pressure in the bellows 54 so that the swimmer may change the degree of buoyancy as desired. Such means is provided by connecting the air space 56 of the bellows 54 with a source of air under pressure and with an exhaust. This is achieved in the embodiment illustrated by utilizing the air pressure chamber 38 both as a source of air pressure and as an exhaust reservoir.

Thus, air under pressure is supplied to the space 56 of the bellows by means of the hand operated, squeezetype air pump 58 of well-known construction. lts inlet is connected through the flexible tubing 60 to the air pressure chamber 38 and its outlet is connected through the check valve 62 and the flexible tubing 64 to the air space 56 of the bellows 54. The valves 66 and 68 associated with the pump function to permit the flow of air under pressure in one direction only, namely from the air pressure chamber to the interior of the bellows 54, as indicated by the arrow.

The check valve 62 also permits flow of air pressure only in the direction from the air pressure chamber to the interior of the bellows, and also is adjustable to require a predetermined minimum air pressure at the outlet of the pump before opening to allow said flow. This predetermined pressure may be varied as desired, but preferably is only slightly greater than that required to extend the bellows 54 and 46.

Air pressure in the bellows 54 is relieved or exhausted to the air pressure chamber 38 by means of the hand operated, squeeze-type air pump 70. This pump may be identical to pump 58 previously described and its associated valves 72 and 74 are arranged to afford movement of air in one direction only, namely from the bellows 54 to the air pressure chamber 38, as indicated by the arrow. An adjustable check valve 76 adjacent the outlet of the pump requires the latter to pressurize the air to a predetermined extent, slightly greater than required to collapse the bellows 54 and 46.

Branch tubings 60 and 64' communicate the tubings 60 and 64 with the second unit 24 illustrated in FIGS. 1 and 2.

The pumps 58 and 70 preferably are located adjacent the chest of the swimmerfor convenient access for hand manipulation during swimming. Thus, if the swimmer desires to submerge to a greater depth in the water the pump 58 is manipulated to further pressurize the bellows 54 with air taken from the air pressure chamber 38. The piston 48 thus is moved upward in the air pressure chamber, decreasing the volume of the latter and allowing additional water to be taken into the water chamber 52.

On the other hand, if the swimmer desires additional buoyancy to move upward to a shallower depth, the pump is manipulated to withdraw air pressure from the bellows 54 and introduce it into the air pressure chamber 38. The piston 48 thus is forced downward in the air pressure chamber, increasing the volume of the latter and expelling a corresponding quantity of water from the water chamber 52.

It is to be noted that the pumps 58 and 70 are merely a convenience to the swimmer in effecting changes in depth of submergence without physical effort on the part of the swimmer. in the absence of the pumps the swimmer merely swims to the desired depth, either below or above an established depth, whereupon the piston 48 moves automatically in the direction to decrease or increase, respectively, the volume of the air pressure chamber 38 to maintain proper buoyance at the attained depth. This automatic adjustment of buoyancy balance is achieved by virtue of the fact that the air pressure within the bellows 54 readjusts automatically to equal the breath exhaust air pressure in the air pressure chamber 38, as well as the water pressure in the water chamber 52, at all levels of submergence.

The embodiment illustrated in FIG. 4 differs from that of FIG. 3 merely in the location and size of the control air bellows 54. Thus, whereas in FIG. 3 the bellows is located concentrically within the water chamber bellows 46, in FIG. 4 it is located concentrically outside the water chamber bellows. Therefore, in FIG. 4 the enclosed air space 56 is of annular shape, being defined between the outer air control bellows 54 and the inner water chamber bellows 46. The mode of operation of the arrangement illustrated in FIG. 4 is substantially identical to that illustrated in FIG. 3.

In the embodiment illustrated in FIG. 5, the water chamber bellows 46, previously described, is replaced by a substantially rigid, hollow tube 80. The tube is open at its bottom end and closed at its inner, upper end by the piston 82. The tube extends freely through an opening in the bottom' wall 36' of the air cylinder 36, and a fluid pressure seal is provided between them, by such means as the O-ring 84 mounted in an annular groove provided in the inner edge of the bottom-wall defining said opening. I

The piston 82 projects outwardly beyond the hollow tube 80 and its periphery is provided with an annular groove which mounts the fluid pressure O-ring seal 86 which slidably engages the inner surface of the air pressure cylinder 36 defining the air pressure chamber 38.

Accordingly, there is provided between the O-ring seals 84 and 86 a closed annular space 88 which defines a compressible control air pressure chamber which functions in the same manner as the control pressure chamber 56 previously described.

If desired, a coil spring 90 may encircle the hollow tube 80, abutting at its bottom end against the bottom wall 36' of the air cylinder and at its upper, inner end against the piston 82. The spring may supplement the action of the closed, compressible air space. Altema tively, the spring may replace the closed, compressible air space, in which case the fluid pressure seal 86 on the piston may be omitted so that the space 88'between the hollow tube and air cylinder becomes a part of the air pressure chamber 38 as in the embodiments illustrated in FIGS. 3 and 4.

It will be understood that when the coil spring 90 is employed, its resistance to compression should be selected so as to provide the same degree of movement of the piston as does the control air pressure bellows, so that the volume of the air pressure chamber 38 provides automatically the appropriate buoyancy at various levels of submergence.

The arrangement illustrated in FIG. 5 may also incorporate the manually controlled pumps 58 and 70 illustrated in FIG. 3, as will be apparent.

The modification illustrated in FIG. 6 represents a simplified arrangement which, although it does not operate automatically to regulate buoyancy, is operable by the swimmer to vary the buoyancy as desired.

Thus, the hollow air cylinder 36 providing the air pressure chamber 38 houses a hollow, elongated, longitudinally collapsible bellows 92 which is sealed at its bottom end to the bottom wall 36' of the cylinder and is closed at its upper end by the piston 94. An opening 50 in the bottom wall of the cylinder communicates the interior of the bellows with water in which a swimmer is to submerge.

Associated with the bellows, and preferably formed integral therewith, is an elongated coil spring 96. The spring abuts at its lower end against the bottom wall of the cylinder and at its upper end against the piston. The spring functions to urge the piston resiliently in the direction to reduce the volume of the air pressure chamber 38, as in the embodiments previously described.

The air pressure chamber communicates through the flexible tubing 98 with the outlet of a manually operated air pressure pump 100, such as the squeeze bulb type previously described. The inlet end of the pump communicates with a source of air, preferably with the breath exhaust outlet 42 of the air pressure regular 16. The tubing 98 also communicates with the inlet to a manually operable valve 102, the outlet of which communicates with the atmosphere, or the water in which a swimmer is submerged. A branch tubing 98 communicates the air pressure chamber of a second buoyancy regulating unit 24, as previously explained.

In the use of the apparatus illustrated in FIG. 6, before the swimmer enters the water, the manual valve 102 is opened to allow the bellows 92 to extend fully into the cylinder, by extension of the coil spring 96, to reduce the volume of the air pressure chamber 38. The valve then is closed, the swimmer enters the water and upends the buoyancy regulating units to allow water to enter the water chambers defined by the hollow bellows 92. Since the volume of the air pressure chamber is reduced to a minimum, the swimmer, submerges easily to a desired depth.

When the desired depth is reached, the swimmer operates the manual pump to force breath exhaust air under pressure into the air pressure chamber 38. The water chamber bellows thus collapses to the extent proportionate to the pressure in the air chamber 38, until buoyancy is achieved.

The embodiment illustrated in FIGS. 7-10 provides a construction which differs from, but operates in the same manner as, the embodiment illustrated in FIG. 3. Thus, the variable volume air pressure chamber 38 is provided by a resilient bellows which is interposed between and sealed by the end plate 112 and movable piston 114, respectively. A pair of spaced control bellows 54 are interposed between and sealed by the piston 1 l4 and the opposite end plate 116.

The end plate 112 and 116 are spaced apart on opposite sides of the piston 114 by means of vertically spaced rods 1 18. These rods also serve as guides for the piston which is provided with openings which slidably receive the rods therethrough.

An opening through the base plate 112 communicates the air pressure chamber 38 with the conduit 40, and openings through the base plate 116 communicate the interiors of the control bellows 54 with the conduit 64, as in the embodiment of FIG. 3.

As in the previous embodiments, the side of the piston 114 opposite the air pressure chamber 38 is exposed to the pressure of water in which a swimmer is submerged. Thus, in the automatic operation of the apparatus, as the piston 114 moves toward the left to increase the volume of the air pressure chamber 38, the air in the control bellows 54 increases progressively in pressure and thus provides a resilient force of progressively increasing magnitude opposing said movement of the piston. The degree of movement of the piston is determined automatically by the balancing of air pressure in the control bellows 54 with the water pressure against the piston 114 and the exhaust air pressure in the air pressure chamber 38.

Manual control for adjusting the air pressure in the control bellows 54 so that a swimmer may change the degree of buoyancy as desired, is provided by the air pumps 58 and 70, as previously described. a

The sliding engagement of piston 114 with rods 118, as provided by the openings 120, may be avoided if desired by shortening the piston to fit between the rods and hinging the piston at one end, for example the bottom end in FIG. 7, to the plate 112. In such construction the control bellows 54 will be located between plate 116 and the divergent end of piston 114, i.e. the end opposite the hinge. Various other forms of construction may be utilized, as will be understood.

It will be apparent that the spring 96 associated with the bellows 92 may be replaced by a bellows, such as the bellows 54 illustrated in FIGS. 3, 4 and 7, to provide the required resilient control of the water chamber bellows. Similarly, the control bellows 54, illustrated in FIGS. 3, 4 and 7, may be replaced by appropriately adjusted compression springs. The bellows of FIGS. 3, 4 and 7 and the closed space 88 provided by the seals 84 and 86 in FIG. are preferred arrangements, however, since they provide automatic operation of the apparatus with minimum complication, and also accominodate use of the manual pumps 58 and 70 for the purpose previously explained.

When a pair of units 24 are utilized as in FIGS. 1 and 2, it will be understood that the bellows 46 and 54, or bellows 92, or springs 90 of both units should have substantially equal resilient resistance to collapsing, so that the volume of the air pressure chambers 38 of both units vary equally and thereby provide proper balance for the swimmer.

It will be further apparent that the air supply cylinder 10, or an auxiliary cylinder similar thereto, may be utilized as the source of air pressure for the chamber 38 and for the control chambers 56 or 88. The arrangement illustrated, utilizing the breath exhaust of the swimmer, is preferred for its economy and minimum bulk.

From the foregoing it will be appreciated that the present invention provides simplified and economical means by which to regulate automatically or manually the buoyancy of a swimmer through various depths of submergence in water and irrespective of the movements and attitudes of the swimmer. That is to say, even should the swimmer upend the buoyancy regulating unit so that the opening to the water chamber is directed upward, proper buoyancy is maintained.

Having now described my invention and the manner in which it may be used, 1 claim:

1. Buoyancy regulating apparatus for underwater swimming, comprising a. means forming an elongated, hollow air pressure buoyancy chamber,

b. means forming an elongated, hollow water chamber sealed from and extending adjustably into said air pressure buoyancy chamber for varying the volume of the latter,

c. resilient means interengaging the air pressure and water chamber forming means and urging the water chamber 'in the direction to reduce the volume of the air pressure buoyancy chamber,

. passageway means communicating the interior of the air pressure buoyancy chamber with a source of air under pressure, and

e. passageway means communicating the interior of the water chamber with water in which a swimmer is to submerge.

2. The apparatus of claim 1 wherein the resilient means comprises seal means between one end of the air pressure buoyancy chamber and the opposite end of the water chamber and forming a compressible air space therebetween.

3. The apparatus of claim 2 wherein the seal means comprises a longitudinally collapsible hollows bellows member sealed at one end to the air pressure chamber and at the opposite end to the water chamber and forming a compressible air space therein.

4. The apparatus of claim 2 including control means communicating said compressible air space selectively with a source of air pressure and exhaust and operable by a swimmer to vary the pressure in said air space relative to the pressure in said air pressure chamber, whereby to vary the volume of the latter.

5. The apparatus of claim 4 wherein the control means comprises a. first air pump means communicatingsaid compressible air space with said air pressure chamber and operable to pump air from said air pressure chamber into said air space, and

b. second air pump means communicating said compressible air space with said air pressure chamber and operable to pump air from said air space into said air pressure chamber.

6. The apparatus of claim 1 wherein the resilient means comprises spring means interengaging the air pressure chamber and water chamber.

7. The apparatus of claim 1 wherein the water chamber comprises a. a longitudinally collapsible bellows member sealed at one end to the air pressure chamber, and

b, piston means closing the opposite end of the bellows member and movable longitudinally within the air pressure chamber for varying the volume of the latter.

8. The apparatus of claim 7 wherein the resilient means comprises a longitudinally collapsible hollow bellows member sealed at one end to the air pressure chamber and at the opposite end to the piston means and forming a compressible air space therein.

9. The apparatus of claim 1 in combination with underwater air supply means including an air pressure regulator having a breath exhaust outlet, the passageway means communicating the interior of the air pressure buoyancy chamber with a source of air under pressure comprising tubing means communicating the interior of the air pressure chamber with the breath exhaust outlet.

10. The apparatus of claim 9 including a. air pump means in the tubing means operable by a swimmer to pump breath exhaust into the air pressure chamber to increase the volume of the latter, and

b. valve means communicating with the air pressure chamber and operable by a swimmer to reduce the pressure in the air pressure chamber to decrease the volume of the latter.

l 1. The apparatus of claim 9 including breath exhaust valve means having an inlet communicating with the regulator exhaust outlet and with the tubing means.

12. The apparatus of claim 9 wherein the resilient means comprises seal means between one end of the air pressure buoyancy chamber and the opposite end of the water chamber and forming a compressible air space therebetween, and the apparatus includes a. first air pump means communicating said compressible air space with said air pressure chamber and operable to pump breath exhaust air from said air pressure chamber into said air space, and b. second air pump means communicating said compressible air space with said air pressure chamber and operable to pump breath exhaust air from said air pressure chamber.

13. The apparatus of claim 1 wherein the resilient means comprises a longitudinally collapsible hollow bellows member sealed at one end to the air pressure chamber and at the opposite end to the water chamber and forming a compressible air space therein.

14. The apparatus of claim 9 wherein the water chamber comprises a. a longitudinally collapsible bellows member sealed at one end to the air pressure chamber, and

b. piston means closing the opposite end of the bellows member and movable longitudinally within the air pressure chamber for varying the volume of the latter.

15. The apparatus of claim 14 wherein the resilient means comprises a longitudinally collapsible hollow bellows member sealed at'one end'to the air pressure chamber and at the opposite end to the piston means and forming a compressible air space therein.

16. The apparatus of claim 15 including a. first air pump means communicating said compressible air space with said air pressure chamber and operable-to pump air from said air pressure chamber into said air space, and

b. second air pump means communicating said compressible air space with said air pressure chamber and operable to pump air from said air space into said air pressure chamber.

17. The apparatus of claim 1 wherein the water chamber comprises a. an elongated, hollow tube extending slidably outward through one end of the air pressure buoyancy chamber and open at its extended end,

b. fluid pressure seal means between the tube and said one end of the air pressure chamber, and c. piston means closing the opposite end of the tube and movable longitudinally within the air pressure chamber for varying the volume of the latter.

l8. Buoyancy regulating apparatus for underwater swimming, comprising a. means including a movable piston defining a hollow air pressure buoyancy chamber capable of being varied in volume by movement of said piston, I

b. the side of the piston opposite the air pressure buoyancy chamber being exposed to the pressure of water in which a swimmer is to submerge,

c. resilient means engaging the piston and urging the latter in the direction to reduce the volume of the air pressure buoyancy chamber, and

d. passageway means communicating the interior of the air pressure chamber with a source of air under pressure.

19. The apparatus of claim 18 wherein the resilient means comprises longitudinally collapsible hollow bellowsmeans fixed at one endand engaging the piston at the opposite end and forming a compressible air space therein.

20. The apparatus of claim 19 including control means communicating said compressible air space selectively with a source of air pressure and exhaust and operable by a swimmer to vary the pressure in said air space relative to the pressure in said air pressure chamber, whereby to vary the volume of the latter.

21. The apparatus of claim 18 including means on the side of the piston opposite the air pressure chamber providing an elongated hollow water chamber sealed from and extending adjustably into said air pressure chamber for varying the volume of the latter, the

resilient means interengaging the air pressure chamber and water chamber for moving the latter in the direction to reduce the volume of the air pressure chamber. 7

22. The apparatus of claim 2 wherein the control means comprises:

-a. first air pump means communicating said compressible air space with said air pressure buoyancy chamber and operable to pump air from said air pressure chamber into said air space, and b. second air pump means communicating said compressible air space with said air pressure chamber and operable to pump air from said air space into said air pressure chamber.

23. The apparatus of claim 18 in combination with underwater air supply means including an air pressure regulator having a breath exhaust outlet, the passageway means communicating the interior of the air pressure buoyancy chamber with a source of air under pressure comprising tubing means communicating the interior of the air pressure buoyancy chamber with the breath exhaust outlet.

24. The apparatus of claim 23 including breath exhaust valve means having an inlet communicating with the regulator exhaust outlet and with the tubing means.

25. The apparatus of claim 25 wherein the resilient means comprises means forming a longitudinally compressible air space fixed at one end and engaging the piston at the opposite end, and the apparatus includes control means communicating said compressible air space with the air pressure buoyancy chamber and operably by a swimmer selectively to transfer breath exhaust air between said air space and air pressure chamber, whereby to vary the volume of the air pressure chamber.

26. The apparatus of claim 25 wherein the control b. second air pump means communicating said compressible air space with said air pressure chamber and operable to pump breath exhaust air from said air space into said air pressure chamber. 

1. Buoyancy regulating apparatus for underwater swimming, comprising a. means forming an elongated, hollow air pressure buoyancy chamber, b. means forming an elongated, hollow water chamber sealed from and extending adjustably into said air pressure buoyancy chamber for varying the volume of the latter, c. resilient means interengaging the air pressure and water chamber forming means and urging the water chamber in the direction to reduce the volume of the air pressure buoyancy chamber, d. passageway means communicating the interior of the air pressure buoyancy chamber with a source of air under pressure, and e. passageway means communicating the interior of the water chamber with water in which a swimmer is to submerge.
 2. The apparatus of claim 1 wherein the resilient means comprises seal means between one end of the air pressure buoyancy chamber and the opposite end of the water chamber and forming a compressible air space therebetween.
 3. The apparatus of claim 2 wherein the seal means comprises a longitudinally collapsible hollows bellows member sealed at one end to the air pressure chamber and at the opposite end to the water chamber and forming a compressible air space therein.
 4. The apparatus of claim 2 including control means communicating said compressible air space selectively with a source of air pressure and exhaust and operable by a swimmer to vary the pressure in said air space relative to the pressure in said air pressure chamber, whereby to vary the volume of the latter.
 5. The apparatus of claim 4 wherein the control means comprises a. first air pump means communicating said compressible air space with said air pressure chamber and operable to pump air from said air pressure chamber into said air space, and b. second air pump means communicating said compressible air space with said air pressure chamber and operable to pump air from said air space into said air pressure chamber.
 6. The apparatus of claim 1 wherein the resilient means comprises spring means interengaging the air pressure chamber and water chamber.
 7. The apparatus of claim 1 wherein the water chamber comprises a. a longitudinally collapsible bellows member sealed at one end to the air pressure chamber, and b. piston means closing the opposite end of the bellows member and movable longitudinally within the air pressure chamber for varying the volume of the latter.
 8. The apparatus of claim 7 wherein the resilient means comprises a longitudinally collapsible hollow bellows member sealed at one end to the air pressure chamber and at the opposite end to the piston means and forming a compressible air space therein.
 9. The apparatus of claim 1 in combination with underwater air supply means including an air pressure regulator having a breath exhaust outlet, the passageway means communicating the interior of the air pressure buoyancy chamber with a source of air under pressure comprising tubing means communicating the interior of the air pressure chamber with the breath exhaust outlet.
 10. The apparatus of claim 9 including a. air pump means in the tubing means operable by a swimmer to pump breath exhaust into the air pressure chamber to increase the volume of the latter, and b. valve means communicating with the air pressure chamber and operable by a swimmer to reduce the pressure in the air pressure chamber to decrease the volume of the latter.
 11. The apparatus of claim 9 including breath exhaust valve means having an inlet communicating with the regulator exhaust outlet and with the tubing means.
 12. The apparatus of claim 9 wherein the resilient means comprises seal means between one end of the air pressure buoyancy chamber and the opposite end of the water chamber and forming a compressible air space therebetween, and the apparatus includes a. first air pump means communicating said compressible air space with said air prEssure chamber and operable to pump breath exhaust air from said air pressure chamber into said air space, and b. second air pump means communicating said compressible air space with said air pressure chamber and operable to pump breath exhaust air from said air pressure chamber.
 13. The apparatus of claim 1 wherein the resilient means comprises a longitudinally collapsible hollow bellows member sealed at one end to the air pressure chamber and at the opposite end to the water chamber and forming a compressible air space therein.
 14. The apparatus of claim 9 wherein the water chamber comprises a. a longitudinally collapsible bellows member sealed at one end to the air pressure chamber, and b. piston means closing the opposite end of the bellows member and movable longitudinally within the air pressure chamber for varying the volume of the latter.
 15. The apparatus of claim 14 wherein the resilient means comprises a longitudinally collapsible hollow bellows member sealed at one end to the air pressure chamber and at the opposite end to the piston means and forming a compressible air space therein.
 16. The apparatus of claim 15 including a. first air pump means communicating said compressible air space with said air pressure chamber and operable to pump air from said air pressure chamber into said air space, and b. second air pump means communicating said compressible air space with said air pressure chamber and operable to pump air from said air space into said air pressure chamber.
 17. The apparatus of claim 1 wherein the water chamber comprises a. an elongated, hollow tube extending slidably outward through one end of the air pressure buoyancy chamber and open at its extended end, b. fluid pressure seal means between the tube and said one end of the air pressure chamber, and c. piston means closing the opposite end of the tube and movable longitudinally within the air pressure chamber for varying the volume of the latter.
 18. Buoyancy regulating apparatus for underwater swimming, comprising a. means including a movable piston defining a hollow air pressure buoyancy chamber capable of being varied in volume by movement of said piston, b. the side of the piston opposite the air pressure buoyancy chamber being exposed to the pressure of water in which a swimmer is to submerge, c. resilient means engaging the piston and urging the latter in the direction to reduce the volume of the air pressure buoyancy chamber, and d. passageway means communicating the interior of the air pressure chamber with a source of air under pressure.
 19. The apparatus of claim 18 wherein the resilient means comprises longitudinally collapsible hollow bellows means fixed at one end and engaging the piston at the opposite end and forming a compressible air space therein.
 20. The apparatus of claim 19 including control means communicating said compressible air space selectively with a source of air pressure and exhaust and operable by a swimmer to vary the pressure in said air space relative to the pressure in said air pressure chamber, whereby to vary the volume of the latter.
 21. The apparatus of claim 18 including means on the side of the piston opposite the air pressure chamber providing an elongated hollow water chamber sealed from and extending adjustably into said air pressure chamber for varying the volume of the latter, the resilient means interengaging the air pressure chamber and water chamber for moving the latter in the direction to reduce the volume of the air pressure chamber.
 22. The apparatus of claim 2 wherein the control means comprises: a. first air pump means communicating said compressible air space with said air pressure buoyancy chamber and operable to pump air from said air pressure chamber into said air space, and b. second air pump means communicating said compressible air space with said air pressure chamber and operable to pump air from said air space into said air pressure chamBer.
 23. The apparatus of claim 18 in combination with underwater air supply means including an air pressure regulator having a breath exhaust outlet, the passageway means communicating the interior of the air pressure buoyancy chamber with a source of air under pressure comprising tubing means communicating the interior of the air pressure buoyancy chamber with the breath exhaust outlet.
 24. The apparatus of claim 23 including breath exhaust valve means having an inlet communicating with the regulator exhaust outlet and with the tubing means.
 25. The apparatus of claim 25 wherein the resilient means comprises means forming a longitudinally compressible air space fixed at one end and engaging the piston at the opposite end, and the apparatus includes control means communicating said compressible air space with the air pressure buoyancy chamber and operably by a swimmer selectively to transfer breath exhaust air between said air space and air pressure chamber, whereby to vary the volume of the air pressure chamber.
 26. The apparatus of claim 25 wherein the control means comprises a. first air pump means communicating said compressible air space with said air pressure chamber and operable to pump breath exhaust air from said air pressure chamber into said air space, and b. second air pump means communicating said compressible air space with said air pressure chamber and operable to pump breath exhaust air from said air space into said air pressure chamber. 